英文關鍵字
20s
academic
adult
attentively
book
campus
casual
caucasian
cheerful
class
classmates
clothing
college
concentrated
concentrating
education
female
focused
folder
four
frowning
happy
higher
knowledge
lesson
listening
male
man
mixedrace
notebook
notes
paper
people
school
serious
smiling
stern
student
taking
thoughtful
university
unsmiling
woman
writing
young